Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161021AbaDJNiw (ORCPT ); Thu, 10 Apr 2014 09:38:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:5578 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030546AbaDJNiu (ORCPT ); Thu, 10 Apr 2014 09:38:50 -0400 Date: Thu, 10 Apr 2014 15:38:55 +0200 From: Oleg Nesterov To: Steven Rostedt Cc: Mathieu Desnoyers , Frederic Weisbecker , LKML , Andrew Morton , Ingo Molnar Subject: Re: [PATCH RESEND 2/2] tracing: syscall_regfunc() should not skip kernel threads Message-ID: <20140410133855.GC12228@redhat.com> References: <1397059882-23063-1-git-send-email-fweisbec@gmail.com> <1397059882-23063-3-git-send-email-fweisbec@gmail.com> <360091921.1294.1397060915052.JavaMail.zimbra@efficios.com> <20140409124249.4081e665@gandalf.local.home> <20140409170505.GA27638@redhat.com> <20140409170616.GC27638@redhat.com> <20140410092842.1f9a8760@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140410092842.1f9a8760@gandalf.local.home> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/10, Steven Rostedt wrote: > > On Wed, 9 Apr 2014 19:06:16 +0200 > Oleg Nesterov wrote: > > > syscall_regfunc() ignores the kernel thread because "it has > > no effect", see cc3b13c1 "Don't trace kernel thread syscalls". > > > > However, this means that a user-space task spawned by > > call_usermodehelper() won't report the system calls if > > kernel_execve() is called when sys_tracepoint_refcount != 0. > > What about doing the set there? That is, we could add a check in the > call_userspacehelper() just before it does the do_execve, that if > sys_tracepoint_refcount is set, we set the TIF flag. But for what? And if we do this, ____call_usermodehelper() needs write_lock_irq(tasklist) to serialize with syscall_*regfunc(). Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/